BRIEF DESCRIPTION OF THE PRIOR ART
The use of closed-loop automatic control systems is well known in the machine tool art, as evidenced, for example, by the patents to Lee No. 4,250,440 and Ehrenfried et al No. 3,663,881, and the use of potentiometers in position sensing systems is broadly disclosed by the patents to Rider No. 3,835,464, Warsher No. 2,625,633, Weisend No. 3,750,134, Wake et al No. 3,857,079 and the Russian Patent No. 586,421. Remote controlled systems broadly are known in the art, as taught by the patent to Shimamura No. 4,248,011, and the use of signal comparison means in automatic vehicle steering systems is shown by the patents to Schmall No. 4,036,323 and Iyeta No. 4,223,624.
While these systems are generally satisfactory in operation, their use is somewhat limited in scope as to actual applications in the field, since they do not readily lend themselves to quick and simple installation on remote control components of existing equipment.